1. Field of the Invention
The present invention relates to a technique for preventing interference between a robot, for welding, and a clamp jig, for fixing a workpiece to be welded by the robot, in offline teaching of the robot.
2. Description of the Related Art
An offline teaching process is widely used in order to, for example, make a program for a welding operation (hereinafter, referred to as a welding program) using a welding robot. One problem in relation to making the welding program is how to deal with the existence of the clamp jig fixing the workpiece to be welded. In other words, interference between a work tool such as a welding torch or a part of a robot arm and the clamp jig may occur when a welding path is determined without considering the existence of the clamp jig and the robot is moved along the determined welding path. In a typically case, as described in one embodiment below, a clamp jig having a bridge shape may be used, which steps over the determined welding path.
In such a case, in an offline teaching of prior art, an operator teaches a path for preventing interference between the clamp jig and the robot. Concretely, the operator teaches a path for preventing interference extending from just before the clamp jig to just after the clamp jig. Further, the operator corrects a welding program such that welding is stopped at the starting point of the path and is restarted at the end point of the path. This operation imposes a heavy workload on the operator and induces deterioration of a work efficiency. An effective technique, for reducing the workload for preventing interference in offline teaching of the welding program and for improving the work efficiency, seems to have not been disclosed in any known document.